Dressing tool



Dec. 24, 1957 H. c. JOHNSTON DRESSING TOOL Filed June 9, 1953 IN VEN TOR.

HAROLD C. JOHNSTON United States Patent 6 DRESSING TOOL Application June 9, 1953, Serial No. 360,555

2 Claims. (Cl. -27) This invention relates to dressing tools and more particularly to a dressing tool for removing accumulated material from the abrasive coating on a flexible, yieldable abrading surface such as a coated abrasive belt, coated abrasive disc, or the like while leaving the underlying abrasive material and base material substantially unaffected and undamaged.

In the use of an abrading tool such as a belt, disc, grinding wheel, stone or the like the surface of the tool tends to fill in or load and substantially to diminish efliciency of operation. With abrasive elements of the coated flexible type, this loading by particles of the material being ground may be more detrimental to efficient grinding than natural wear of the abrasive surface. In the case of hard, rigid abrasive elements, such as wheels, which are composed of abrasive material for a substantial radial depth such loading is overcome by means of a dressing tool provided with one or more cutting elements of great hardness such as a diamond point dresser, a dresser using hardened steel cutter units, or similar instruments to provide a new abrading surface, this operation being repeated a number of times.

In the case of tools using a coated flexible or yieldable abrasive surface, however, the abrasive element comprises an underlying supporting surface or base such as an endless fabric, plastic or fibrous webbing or other supporting material in the case of a belt, or an underlying plate of fibrous or plastic material in the case of a disc, with a relatively thin layer of particles of abrasive materials affixed to the working surface by a suitable adhesive. If such abrasive layer were cut away as is frequently done in the case of an abrasive wheel, the usefulness of the coated element would be impaired and its life materially shortened. Abrasive belts and to a lesser degree abrasive discs are relatively expensive, and it is accordingly desirable to maintain their working surfaces in clean dressed condition by means which will rid them of clogging particles while at the same time leaving the relatively yieldable underlying coated abrasive surface substantially unaffected and undamaged.

In accordance with the present invention, instead of using a rigid dressing tool working against a rigid abrasive wheel, an inherently yieldable tool is used to dress a yieldable abrasive member. The present tool does not employ diamond point or equivalent metal disc cutters, but utilizes the flexible tooth cutters in the form of a wire brush mounted in a dressing head for free rotation therein and adapted to run in working engagement with the flexible abrasive coating on a belt, disc, or the like. The bristles are closely arranged and while they are relatively short in length and stiff, they retain a yieldable characteristic and in operation pick or work into the movable and yieldable surface of the abrasive member, to remove foreign matter therefrom without substantially affecting the abrasive material or the supporting base on which it is retained.

As the tool in use is moved back and forth across the face of the rapidly moving belt or disc, the brush ice rotates freely and develops substantial axial thrust. Means are included on both the dressing head and the spool for taking this thrust, which by reason of the speed of rotation are subjected to substantial wear. Inasmuch as it is necessary for the surface of the brush to be maintained in proper alignment with the surface being cleaned, it is desirable from the point of view of proper operation and economy that these worn parts may readily be replaced. Accordingly provision is made for replacing the brush as desired, and also the bearing pins which support the brush, so that replacement may be made at relatively small cost without necessity for replacing the entire tool.

It is accordingly a principal object of the invention to provide a hand operated dresser or cleaning tool for removing accumulated foreign material from a relatively yieldable coated abrasive belt or coated member without adversely affecting the abrasive surface or the flexible base fabric or other supporting material thereof, and thereby prolonging its effective life.

It is a further object to provide such a dresser including a flexible tooth cutting member or cleaning brush and supporting bearings therefor which are adjustable as they become worn to maintain the member in proper alignment, and which may be replaced separately as desired without replacement of the entire tool.

It is also an object of the invention to provide such a tool which is simple and rugged in construction, which is long-lived, and which may be economically manufactured.

Other objects and advantages will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawing Fig. 1 is a perspective view showing a dressing tool in accordance with the present invention in use in dressing a flexible coated abrasive belt;

Fig. 2 is a fragmentary section of such a belt on an enlarged scale showing the construction thereof;

Fig. 3 is a side elevational view of such a dresser, on a larger scale;

Fig. 4 is a front elevational view on the same scale as Fig. 3 showing the cylindrical Wire brush mounted in the head in proper operating position; and

Fig. 5 is a view similar to Fig. 4, partly broken away and in section to show the construction.

Referring to the drawing, which discloses a preferred embodiment of the invention, Fig. 1 shows a dresser in accordance with the invention in working position for removing accumulated foreign material indicated diagrammatically at 10 (Fig. 2) from the flexible coated abrasive surface 11 carried by the relatively yieldable underlying fabric or supporting material 12 of a moving abrasive belt 13, passing in front of a back-up plate 14. The dresser embodies a handle 15 carrying a dressing head 16 including spaced parallel side walls 17 connected by an apron 13. A pair of threaded pins 19 and 20 are screwed into opposing bores in side walls 17 adapted to receive them, the inner ends of the pins being reduced at 21, thus providing shoulders or bearing portions 22. One of the pins may conveniently be in the form of a cap screw having a flat sided head 23 to facilitate turning it with a wrench or the like, whereas the other is preferably slotted at 24 to facilitate axial adjustment of its position with respect to side walls 17 and provided with a locking means such as locknut 25 for securing it in the desired position. As appears from Figs. 1 and 3, substantially the entire face of head 16 opposite handle 15 is open so that the cylindrical face of the brush projects forward and may easily be brought into contact with the moving flexible abrasive coated surface.

The tool is adapted to be held in working position on a fixed support such as table adjacent the moving coated surface of the belt, and to facilitate holding it in working position handle 15 may conveniently include a first grip portion adjacent to and aligned with the head and a second ofifset grip portion 31 and gripping means such as the ridges or knurls 32 shown in the drawing. Side walls 17 may also be provided with feet 33 to assist sliding and fulcruming movement of the tool with respect to support 30. The tool furthermore is preferably somewhat heavy for resisting forces tending to throw it out of line in use and the handle and head may conveniently be formed integrally as a casting.

A dressing member 35 is rotatably mounted in the head on pins 19 and 20 adapted to run freely in Working e11- gagement with the flexible coated abrasive surface 11. This member comprises a spool 36 carrying flexible tooth cutters in the form of a cylindrical wire bristle brush 37. The wire bristles 38 should be sufliciently stiff to clean from the belt an accumulation of relatively hard abraded material such as steel, copper, brass, bronze or the like, as well as softer materials such as wood or plastic, while being sufficiently flexible so as not to damage the relatively yieldable coated abrasive surface itself. They are accordingly closely arranged and relatively short in length in relation to the diameter of the cylinder so as to form a relatively stiff firm brush construction, while at the same time should be sufficiently long to afford a reasonable life, and additional rigidity is provided by the end members 39 of the spool.

Means for taking the axial thrust of the dressing member developed in use are provided on the spool and the dressing head by flanges 40 axially positioned on the spool adapted to be received against shoulders 22 as the dressing tool is moved back and forth across the moving coated surface. By adjusting the position of pin 20, flanges 40 may be spaced sufficiently close between shoulders 22 so as to limit axial play, while avoiding binding restriction which would interfere with the free rotation of the brush as it is rotated by contact with the rapidly moving yieldable coated abrasive surface.

The brush rotating freely at a surface speed approximately corresponding to that of the loaded surface develops in use a scraping and cleaning action of the bristles against the coated surface, which by reason of the flexibility and resilience of the underlying supporting material tends to yield somewhat to the pressure of the brush and to result in a picking action. The flexible tooth cutters 38 thus tend to scrape and pick away the relatively free loaded material, while sliding over and past the underlying abrasive particles secured and fixed in the underlying surface, leaving them sharp and clean again, Without any shearing action such as is effected by the hard non-yielding cutters used for removing the surface of a rigid abrasive wheel or the like. Wear of the parts of the dresser resulting from such drag may be compensated for by adjusting the movable pin 20 and locking it in place after it is adjusted by lockout 25.

When the brush member becomes worn to the point of inefliciency it may be replaced at relatively small cost by loosening both pins and adjusting a new brush in place. Likewise if pins 19 and 20 become too worn in use they also may be replaced, separately if desired. Thus the wearing parts of the dressing tool may easily be replaced at relatively small cost, while the handle and head need not be replaced and will last practically indefinitely.

The tool may be made in any convenient size depending largely on the size and nature of the coated abrasive surface to be cleaned. It should preferably be heavy enough to resist being thrown out of position on its support as it is passed back and forth against the rapidly moving coated surface in use, while at the same time handling easily and being sufficiently small to fit, if desired, into a relatively confined space. For general use a tool having a brush 1 /2" in axial length with an outside diameter including that of the spool of 1 /2", and with a plate 14 shown in Fig. l, a pulley, roller or the like.

the handle and dressing head in proportion, has proved entirely satisfactory.

While the invention is illustrated and described herein in relation to dressing a coated abrasive belt, it is apparent that it is also applicable to dressing other flexible relatively yieldable moving coated abrasive surfaces in which it is desired to remove the abraded material loaded thereon while leaving the coated surface itself and the underlying supporting base substantially unaffected. It may conveniently be used to clean coated abrasive surfaces in either the vertical position shown in Fig. 1 or in a horizontal position, and may be applied at substantially any point on the belt at which the coated surface is sulficiently supported to present a firm though yieldable surface to the cylindrical face of the tool formed by the bristles, by reason either of the comparative stiffness of the flexible underlying supporting material to which the abrasive coating is adhered, or of being supported at its opposite face by a backing member such as the back-up The dressing tool may be also used for either wet or dry application, depending on the nature of the loaded material to be cleaned and conditions of use.

It will be found in using the dressing tool that a relatively few passes backward and forward across the face of the coated surface should be sufficient to clean the loaded material. The amount of pressure will depend largely on the speed at which the coated surface is moving, the comparative yieldability and resilience of the supporting member, the nature of the material to be removed, and similar factors, only such pressure being necessary as will maintain the bristles in scraping and picking contact with the coated surface.

The invention thus provides a simple, rugged, satisfactory dressing tool for dressing moving relatively yieldable surfaces having a relatively thin abrasive coating thereon, which maintains their abrasive efficiency and will substantially lengthen their useful life, in which the parts subject to wear may readily and easily be replaced at relatively small expense, and which is relatively inexpensive to produce.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. A manually operated flexible tooth cleaning tool for removing accumulated material from the abrasive surface of a moving flexible abrasive member having a thin abrasive coating thereon, comprising a head, an elongated handle including a first grip portion adjacent to and aligned with said head and a second grip portion spaced from said head and offset at an angle to said first grip portion providing for accurately controlling the working position of said cleaning tool with respect to said abrasive surface, said head and handle being of cast metal providing weigh-t for facilitating control of said tool in said working position, substantially the entire face of said head opposite said handle being open, a cylindrical cleaning brush freely rotatably mounted in said head on a fixed axis and adapted to rotate in working engagement with said moving abrasive coating when passed thereacross in said working position, and means for mounting said brush in predetermined position and alignment for rotation about said fixed axis with its cylindrical face opposite said handle projecting forward from said head for presenting said cylindrical face against said moving surface under controlled pressure to produce a picking action thereagainst for removing said accumulated material while leaving said abrasive coating and the underlying flexible base substantially unaffected.

2. A manually operated cleaning tool having a flexible wire brush dressing member for removing accumulated material from the abrasive surface of a moving flexible abrasive member having a thin abrasive coating thereon, adapted for ready replacement of said dressing member, comprising a head, an elongated handle including a first grip portion adjacent to and aligned with said head and a second grip portion spaced from said head and ofiset at an angle to said first grip portion providing for accurately controlling the working position of said cleaning tool with respect to said abrasive surface, said head and handle being of cast metal providing weight for facilitating control of said tool in said working position, substantially the entire face of said head opposite said handle being open, a cylindrical flexible wire bristle brush cleaning member freely rotatably mounted in said head on a fixed axis and adapted to rotate in working engagement with said moving abrasive coating when passed thereacross and pins extending inwardly from the sides of said head positioned to support said dressing member in predetermined position and alignment for rotation about said axis with its cylindrical face opposite said handle projecting forward 20 from said head for presenting said cylindrical face against said moving surface under controlled pressure to produce a picking action thereagainst for removing said accumulated material while leaving said abrasive coating and the underlying flexible base substantially unaffected, said supporting pins including at least one pin movable axially with respect to said dressing member for adjusting the position of said dressing member with respect to said head and said handle to provide limited axial play in said brush.

References Cited in the file of this patent UNITED STATES PATENTS 342,484 Wade May 25, 1886 491,331 Blair Feb. 7, 1893 1,039,262 Courtney Sept. 24, 1912 1,425,152 Viers Aug. 8, 1922 1,445,627 Kissner Feb. 20, 1923 1,480,263 Hoffman Jan. 8, 1924 1,583,587 Flynn May 4, 1926 1,663,059 Peterson Mar. 20, 1928 2,469,871 Eaton May 10, 1949 2,618,399 Stratman Nov. 18, 1952 2,632,583 Allen Mar. 24, 1953 FOREIGN PATENTS 829,086 France Mar. 7, 1938 

